The present invention relates generally, as indicated, to a fluid flow controlling valve and, more particularly, is directed to a three-position, self-centering valve for controlling the delivery of fluid to and the venting of fluid from fluid actuators and the like.
One exemplary type of fluid actuator with which the valve of the invention may be utilized produces a linear mechanical displacement output upon actuation or energization in response to a fluid input, and that mechanical displacement output may be employed to do work on an external device. Such a fluid actuator, for example, includes a body or casing within which a variable volume chamber is formed on one side of a piston, and when fluid pressure in the chamber is increased by supplying fluid thereto to energize the actuator, increased force on the piston out-strokes or moves the same in the cacing to enlarge the chamber. A piston rod coupled to the piston moves therewith to provide the linear mechanical displacement output of the actuator. A return spring in the casing, for example, would normally urge the piston and piston rod toward de-energized in-stroked position to maintain a minimum volume of the chamber when fluid is vented therefrom in preparation for a subsequent energization of the actuator.
Moreover, a plurality of such fluid actuators may be employed in a mechanical system to provide selective actuation or operation of various portions of such system. For example, two fluid actuators may be positioned relative to a linkage to provide opposite operation of a switch, respectively. Energization of one of the fluid actuators, then, would cause closure of the switch and energization of the opposite fluid actuator would effect opening of the switch. Such a system is mentioned for exemplary purposes only, and it will be appreciated that the valve of the present invention, as is described in more detail below, may be used for selectively energizing and de-energizing or otherwise operating other fluid responsive actuators, systems, and the like.